1. Field of the Invention
This invention relates to an orientation device and a magnetization device for use in housing a rotor core of a magnet embedded type rotor inside for a rotary electric machine such as an electric motor or a generator to form permanent magnets in slits for each magnetic pole of the rotor core, and particularly to an orientation device capable of efficiently orientating resinous magnets disposed in slits of a rotor core and a magnetization device capable of efficiently magnetizing the orientated resinous magnets and the like.
2. Description of the Related Art
Heretofore, in an embedded magnet type rotor, orientation of resinous magnets 3 filled in slits 2 for each magnetic pole of a rotor core 1 has been performed through an arrangement as shown in FIG. 6. That is, a forming die 7 was used which comprises a plurality of permanent magnets 5 disposed along the outside circumference of a rotor core housing section 4 at the same intervals as the slits 2 with their magnetic poles of the same polarity adjacent to each other, and a plurality of pole pieces 6 disposed between the plurality of permanent magnets 5 along the outside circumference of the rotor core housing section 4.
The rotor core 1 is disposed in the rotor core housing section 4, and as shown in FIG. 6 by a dashed line, magnetic flux is generated heading from the plurality of permanent magnets 5 through the pole pieces 6 toward the resinous magnets 3 so as to orientate the resinous magnets 3 filled in the slits 2.
However, since in the orientation method using a forming die 7 as described above, magnetic resistance of the slits 2 is larger than that of the rotor core 1, magnetic flux generated by the permanent magnets 5 avoids the resinous magnets 3 filled in the outermost slits 2a of the rotor core 1, as shown in FIG. 7 by dashed lines, resulting in an insufficient orientation of the outermost resinous magnets 3.
In a rotary electric machine using such an embedded magnet type rotor, since the magnitude of the output torque generally depends on the magnetic flux generated by the resinous magnets 3, if the orientation of the resinous magnets 3 is insufficient and the magnetic flux from the resinous magnets 3 decreases, the output torque is decreased, which lowers the performance for the rotary electric machine.
Such a problem arises not only at the time of the orientation of resinous magnets, but also arises at the time of magnetization of permanent magnets.
In view of the foregoing, an object of this invention is to provide an orientation device capable of efficiently orientating resinous magnets filled in slits of a rotor core, and a magnetization device capable of efficiently magnetizing permanent magnets disposed in the slits of the rotor core.
To achieve the former of the foregoing object, the orientation device according to claim 1is characterized by an orientation device adapted to house a rotor core of an embedded magnet type rotor inside for orientating resinous magnets filled in slits for each magnetic pole of the rotor core, said orientation device comprising a plurality of permanent magnets disposed at the same intervals as said slits with their magnetic poles of the same polarity adjacent to each other, along the outside circumference of a rotor core housing section for housing said rotor core, and a plurality of pole pieces made of a ferromagnetic material and disposed between said plurality of permanent magnets, wherein the width of said pole piece at the end on the side of said rotor core housing section is smaller than that of an outermost slit of said rotor core between opposite ends thereof.
In addition, the invention according to claim 2 is characterized by the orientation device according to the invention of claim 1, wherein the width of said permanent magnet is larger at the end on the side remote from said rotor core housing section than at the end on the side of said rotor core housing section.
Further, the invention according to claim 3 is characterized by the orientation device according to the invention of claim 1 or 2, wherein a member disposed around said pole pieces and said permanent magnets is made of a non-magnetic material.
On the other hand, to achieve the former of the foregoing object, the orientation device according to claim 4 is characterized by an orientation device adapted to house a rotor core of an embedded magnet type rotor inside for orientating resinous magnets filled in slits for each magnetic pole of the rotor core, said orientation device comprising a plurality of permanent magnets made of a ferromagnetic material and disposed at the same intervals as said slits along the outside circumference of a rotor core housing section for housing said rotor core, solenoid coils wound on said pole pieces, and a connection member made of a ferromagnetic material and connecting the outside circumferential portions of said pole pieces, wherein the width of said pole piece at the end on the side of said rotor core housing section is smaller than that of an outermost slit of said rotor core between opposite ends thereof. Regarding the pole pieces and the connection member, they may be provided in separated relation, or in integrated relation.
Further, to achieve the latter of the foregoing object, the magnetization device according to claim 5 is characterized by a magnetization device for magnetizing permanent magnets disposed in slits for each magnetic pole of the rotor core, said magnetization device comprising a plurality of permanent magnets made of a ferromagnetic material and disposed at the same intervals as said slits along the outside circumference of a rotor core housing section for housing said rotor core, solenoid coils wound on said pole pieces, and a connection member made of a ferromagnetic material and connecting the outside circumferential portions of said pole pieces, wherein the width of said pole piece at the end on the side of said rotor core housing section is smaller than that of an outermost slit of said rotor core between opposite ends thereof. Regarding the pole pieces and the connection member, they may be provided in separated relation, or in integrated relation, as in the invention according to claim 4. In addition, regarding the permanent magnets disposed in the slits, they may be formed by resinous magnets filled in the slits and orientated, or may be sintered magnets inserted in the slits.
Therefore, since in the orientation device according to claim 1 and 4, the width of the pole piece at the end on the side of said rotor core housing section is smaller than that of an outermost slit of said rotor core between opposite ends thereof, magnetic flux generated by permanent magnets or solenoid coils for orientation is prevented from avoiding resinous magnets filled in the outermost slits of the rotor core, which enables efficient and sufficient orientation of the resinous magnets filled in the slits for each magnetic pole of the rotor core, whereby a larger output torque is effected in a rotary electric machine using such an embedded magnet type rotor, improving performance for the rotary electric machine.
If the slit of the rotor core has a measurable thickness, the width of the pole piece at the end on the side of the rotor core housing section may be made smaller than the maximum width of the outermost slit of the rotor core between opposite ends thereof.
Further, since in the orientation device according to claim 2, the width of the permanent magnet is larger at the end on the side remote from the rotor core housing section than at the end on the side of the rotor core housing section, magnetic resistance of the pole piece in the side remote from the rotor core housing section will increase compared to when permanent magnets with opposite ends of the same width are used. As a result, magnetic flux passing through the pole pieces on the sides of the rotor core housing section is increased, providing effective and sufficient orientation of resinous magnets filled in the slits of the rotor core.
Furthermore, since in the orientation device according to claim 3, a member disposed around the pole pieces and the permanent magnets is made of a nonmagnetic material, magnetic resistance of the permanent magnets in the outside circumferential sides will increase. As a result, magnetic flux passing through the pole pieces on the sides of the rotor core housing section is increased, providing effective and sufficient orientation of resinous magnets filled in the slits of the rotor core.
On the other hand, since in the magnetization device according to claim 5, the width of the pole piece at the end on the side of the rotor core housing section is smaller than that of an outermost slit of the rotor core between opposite ends thereof, magnetic flux generated by solenoid coils for magnetization is prevented from avoiding permanent magnets filled in the outermost slits of the rotor core, which enables efficient and sufficient magnetization of the permanent magnets disposed in the slits for each magnetic pole of the rotor core, whereby a larger output torque is effected in a rotary electric machine using such an embedded magnet type rotor, improving performance for the rotary electric machine.